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Northwest Africa 14638
Basic information Name: Northwest Africa 14638
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 14638
Observed fall: No
Year found: 2021
Country: (Northwest Africa)
Mass:help 280 g
Recommended:  Howardite    [explanation]

This is 1 of 421 approved meteorites classified as Howardite.   [show all]
Search for other: Achondrites, HED achondrites, and Howardites
Comments: Approved 19 Mar 2022
Writeup from MB 111:

Northwest Africa 14638 (NWA 14638)

Howardite, (Northwest Africa)

Purchased: 2021 Nov

Classification: HED achondrite (Howardite)

History: The meteorite was purchased from a group of meteorites hunters in Nouadhibou, Mauritania in November, 2021.

Physical characteristics: Dark grayish rock without fusion crust.

Petrography: The meteorite shows a grayish interior and is a polymict breccia composed of 5 mm lithic clasts (fine-grained basaltic, gabbroic, impact melt) mineral clasts set into a fine-grained clastic mineral matrix. Predominant minerals are Fe-rich low-Ca pyroxenes with augite exsolution lamellae, diogenetic low-Ca pyroxene (about 25 vol%), zoned low-Ca pyroxene, olivine, and calcic plagioclase all with highly variable grain sizes. Diogenetic low-Ca pyroxenes are up to 800 µm in size. Minor phases include silica, Ti-poor chromite, ilmenite, FeS, and metallic iron. Contains secondary calcite and barite.

Geochemistry: low-Ca pyroxene: Fs57.0±0.2Wo5.0±0.3 (Fs56.7-57.2Wo4.6-5.3, FeO/MnO=27-29, n=7); augite exsolution lamellae: Fs24.0±1.1Wo40.0±2.2 (Fs22.5-25.9Wo35.9-42.7, FeO/MnO=25-27, n=7); diogenetic low-Ca pyroxene: Fs34.9±0.6Wo5.3±1.0 (Fs33.9-36.0Wo3.9-7.4, FeO/MnO=25-27, n=7); zoned low-Ca pyroxene: Fs27.5±5.3Wo1.6±0.2 (Fs21.0-33.1Wo1.3-1.8, FeO/MnO=25-30, n=7); olivine: Fa18.1±0.1 (Fa17.9-18.3, FeO/MnO=39±2, n=7); magnesian olivine: Fa9.3±0.1 (Fa9.2-9.3, FeO/MnO=33±3, n=7); calcic plagioclase: An87.7±3.2 (An83.4-91.3, n=7)

Data from:
  Table 0
  Line 0:
Place of purchase:Nouadhibou, Mauritania
Date:P 2021 Nov
Mass (g):280
Shock stage:moderate
Weathering grade:moderate
Fayalite (mol%):18.1; 9.3
Ferrosilite (mol%):57.0; 24.0; 34.9; 27.5
Wollastonite (mol%):5.0; 40.0; 5.3; 1.6
Classifier:A. Greshake, MNB
Type spec mass (g):20.2
Type spec location:MNB
Main mass:Salamu Ali
Comments:Submitted by Ansgar Greshake
   and collections
MNB: Museum für Naturkunde, Invalidenstraße 43, D-10115 Berlin, Germany (institutional address; updated 24 Dec 2011)
References: Published in Meteoritical Bulletin, no. 111, in preparation (2022)
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     This is 1 of 8559 approved meteorites from (Northwest Africa) (plus 1896 unapproved names)

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